Anopheline mosquitoes constitute the primary vectors of malaria. Recent developments in mosquito genomics as well as paradigm-shifting insights gleaned from other areas of biology provide exciting opportunities to greatly enhance our understanding of mosquito genetics, physiology, and behavior. New insights in mosquito biology will undoubtedly facilitate the development of novel strategies to combat malaria and other mosquito-borne diseases. The long term objectives of the proposed research are to determine the biological functions of a novel class of gene regulatory molecules named microRNAs (miRNAs) in Anopheles gambiae and uncover novel approaches to control vector-borne diseases by investigating the potential roles of miRNAs in processes that are intimately linked to mosquito vectorial capacity. miRNAs are approximately 22 nucleotide long non-coding RNAs that modulate the expression of cellular genes by binding to cognate mRNA for cleavage or translational repression. In some organisms, microRNAs serve as key regulatory molecules during embryonic development, stem cell division, neurogenesis, haematopoietic cell differentiation, and cell death. They are also implicated in the control of viral infections and cancer. MiRNAs represent a vast and untapped research area in vector biology that could greatly expand our current knowledge and provide potential targets for control of vector-borne diseases. We have recently identified a number of putative mosquito-specific miRNA by comparing conserved non-coding sequences between An. gambiae and Aedes aegypti. Our preliminary miRNA array data indicate that the levels of several miRNAs change significantly after a blood meal. During this exploratory R21 project, we will 1) Identify a broad spectrum of miRNAs from An. gambiae, using an integrated, two-track approach that involves genome-scale computational prediction and direct cloning, 2) Determine the spatiotemporal profiles of miRNA expression in An. gambiae before and at different time points after a bloodmeal. We will provide information on a large repertoire of miRNAs that will serve as the foundation for future research. We will focus on identifying those miRNAs likely to regulate bloodmeal-triggered processes in different tissues. Overall, the proposed research will facilitate vector research by starting to fill a major gap in our understanding of mosquito biology and contribute to novel strategies to control mosquito-borne infectious diseases. [unreadable] [unreadable] [unreadable]